1984 Series 3 , 4.2. Really having trouble and need advice on how to test the Air condition power supply . Replaced the pump and gas and everything was working fine. Unit has been working good but I did hear the fans cut in and out a couple of times. How I have nothing when I turn the system on. Can hear the flaps move with vacuum. No fans and no power at the compressor. Have checked the fuses that I think are related. The only ones I could find faulty are # 8 Cigar lighter, Glove box # 9 Fog rear guard. No power going in on these fuses.
The more I read and search the more confused I become. Have looked at the Wiring diagram . Is there a step by step checklist. Thanks for your time and experience.

 

Hi,
on the side of the front of the compressor there is a black plastic "fuse" with wires connected to it. This fuse is mounted to a bracket.

the main compressor fuse is located on the passenger side fuse box in left hand drive cars. Look at the legend behind the under dash panel access "door". same with the fans fuse. Then there is a hidden inline fuse on the passenger side transmission tunnel, under the carpet, near the firewall, in a plastic fuse holder. Remove the upholstery "knee" panel where the heater Vent is to search for it.

the compressor itself has an overpressure switch located on the rear of the compressor. Almost like a "reset". Look carefully to see if it has popped out. This assumes you have the Harrison compressor from General Motors, which is the standard compressor in the Series 3 XJ-6.

The fan speeds are controlled by a large Relay with many wires connected to it, located behind the driver's side upholstery "knee" panel where the floor heater vent is. Same as the passenger side panel.

if no luck, contact www.jag-aire.com/

 

Hi. Thank you for your reply. Have found and checked all the fuses. Have no power going to the Ranco thermostat. Right hand drive car. Tucked up near the hand brake and hard to get to. Fuse is good but no power going to it. Have power at the Relays .Passenger side, Brown heavy wire screw connected.
If I run a hot wire to the Compressor the clutch will pull in. The small fan will run, this has been changed to run when the air conditioner is turned on.
Could it be an Ignition switch power out failure .
Thanks

 

do you mean the auxiliary cooling fan in the front of radoator under bumper has been modded to run with compreasor ?? Yes, that is a common mod, I did it to my '84 too.

Contact Gary at Jag Aire, he can be of better help with the no power to Ranco issue. Maybe Doug here will know.

 

Make sure to check the fuses and fuse holders for corrosion. And.....sometimes the wire will break inside the fuse just inside the metal cap where it is hard to see.

You found all four climate control fuses?

Power to the Ranco (and other things) come from the mode switch.

Also, for the heck of it, bypass the water temp switch that's mounted on the inlet pipe to the heater core; just remove the wires and jump them together. Or use the test leads tucked away in the console for the same purpose. I'll find a pic for you.

Cheers
DD

 

Actually it's the connectors that are gray, not the wires



Cheers
DD

 

Thanks for your help.
I will check the 2 grey connectors for power and jump them together.
There is power at the heavy brown, white strip wire on the large multi wire switch unit. I do have a spare untested unit from a parts car. Might swap it out and see if any improvements.
Thanks

 

Quote:

There is power at the heavy brown, white strip wire on the large multi wire switch unit.

That's the relay pack. Clean/check/tighten the wires. They're often corroded or even scorched

Cheers
DD